This application claims the priority of German patent 198 29 756.4, filed Jul. 3, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to an apparatus for the actuation of a passenger safety system in a motor vehicle which is controllable at the input side at least by a deceleration sensor and comprises a signal evaluation with a programmable actuation logic as well as a plurality of output stages which in the event of actuation issue a firing current to the particular passenger safety components that are to be actuated and are adapted in their electrical/electronic performance to the particular passenger safety component. The invention also relates to a method for adapting such an actuation control apparatus to the existing components of a passenger safety system of a vehicle.
Various models of vehicles are equipped with different passenger safety systems and corresponding actuation control apparatus. There are vehicles with belt tighteners, airbags on the driver and passenger side, deployable roll bars, side air bags, window bags, knee bags and back seat air bags. Usually a model contains only a selection of these passenger safety components.
Different variants of equipment are provided regarding sensing devices for judging conditions relating to the passengers, such as whether seat belts are fastened, seat occupancy by a person or a child, passenger position or passenger weight etc., the state of which affects the decision to deploy, since the restraining devices are activated depending on the severity of an accident and the condition of the passengers recognized by means of a deceleration sensor (known, for example, from German patent document DE 40 23 109 A1). Thus, depending on whether the passenger is belted or not, for example, different deployment thresholds for deploying the airbag are set for the deceleration signal.
Different equipment is also available with regard to the sensing system for detecting factors relating to crash parameters. For example, an anticipatory or pre-crash sensing system may be present which detects by means of radar measurement, for example, the relative velocity of motion toward the object of a collision just before the crash event and feeds this information to the actuation control device in order to influence the decision to actuate (known, for example, from German patent document DE 44 26 090 A1). It is also known to detect crash parameters by deformation sensors disposed near the outer skin of the vehicle's body, which measure for example the rate of intrusion, so as to indicate the collision energy based on the deformation and velocity of the intrusion (known, for example, from German patent document DE 43 24 753 A1).
It is known to use for every model variant a specific control apparatus adapted to the multi-component passenger safety system and the sensing equipment on hand, but this makes stocking the equipment very expensive. To keep the many various control apparatus within bounds, there is an increasing tendency in car manufacture to install a control apparatus covering all variants and to adapt it in a one-time parametrization procedure to the desired variant (compare German patent document DE 196 18 161 C1, for example). This can be done by means of coding switches to be set manually or by entering an appropriate data set into a nonvolatile memory. Applied to an actuation control apparatus, such parametrization consists especially in informing the actuation control apparatus about which passenger safety components and which sensing equipment for detecting factors relating to the passengers and/or to the crash parameters are present in the vehicle. As a result of the parametrization the final stages provided in the actuation control apparatus are shut off from the passenger safety components not installed in the vehicle or just the tests of the final stages which recognize the absence of a module are ignored. Also, all self-testing procedures are adjusted to the specific model variant so that no unnecessary error signals will be generated due to passenger safety or sensory components that are not provided. Lastly, the conditions for actuation in the individual end stages which fire the primer capsules of the associated passenger safety components are adjusted according to the sensory components that are present.
One typical actuation control apparatus covering all variants is controlled at the input end at least by a deceleration sensor and comprises a signal evaluation with a programmable actuation logic as well as several end stages (driver stages) which, in case of actuation, send an actuation current to the passenger safety components that are to be operated in the particular case and must be present in a number corresponding to the maximum equipment. The output stages must be adapted in their design to the primer capsule or in general to the actuator of the associated passenger safety component, and especially the output stages must be able to deliver a sufficient ignition current. The term "actuator" here comprises both the primer capsule and the actuation mechanism in reversible safety systems, such as for example a reversible belt tightener.
European patent document EP 0 842 824 A1 discloses an actuation control apparatus in which each output stage forms together with a memory a module which stores activation information relating to the controlled primer capsule. For example, a threshold value of "1" is assigned to the modules for the belt tighteners and stored, and a threshold value of "2" is assigned to the modules for the airbags and stored. The default threshold values are established to depend on the sensing equipment for detecting factors relating to the passengers or to crash parameters for the purpose, for example, of setting a maximum threshold level so as to suppress the deployment of a front seat passenger airbag if that seat is unoccupied. In the case of a dangerous collision the central unit of the actuation control apparatus conveys parallelly to all modules the threshold value corresponding to the class of accident detected, e.g., "1" or "2", as controlling information. Then only those output stages are activated whose activation information or threshold value is in a predetermined relationship to the conveyed activation information or threshold. The decision whether the particular output stage is to be activated in the accident is performed therefore in the modules themselves, not centrally. The central unit and the interface to the output stages are thus unburdened by the parallel decision making. A disadvantageous high interface frequency can thus be avoided and nevertheless rapid activation is made possible. Even if the activation information stored in the module can be flexibly established, it is however also referred to the associated output stage, which in turn is adapted to a fixedly associated safety component.
German patent document DE 196 27 877 A1 discloses an activation control apparatus with a safety condenser (autarchic condenser), which in the event of a failure of the on-board wiring can simultaneously provide the actuation energy for the activation of several safety components. The activation current of each actuator is pulse-width modulated such that the firing energy required for the particular actuator is established through the pulse-pause ratio of the activation current. Thus in comparison with the state of the art, where a separate autarchic condenser is used for each output stage, a saving is achieved because with the one autarchic condenser several actuators can be supplied simultaneously.
In a generic control apparatus comprising all equipment variants, output stages for passenger safety components not incorporated in the vehicle remain unused and the corresponding terminals are not occupied. This is unavoidable, as a rule, because many components, such as the deployable roll bar and rear-seat airbags are hardly ever present together in the same vehicle. In view of the rapidly improving availability of various passenger safety components the range of different passenger safety components that have to be covered is becoming ever greater, and this contributes to the fact that the percentage of output stages constructed in an actuation control apparatus but not needed also becomes constantly greater.
It is the object of the invention to devise an actuation control apparatus which can be used for a series of equipment variants of passenger safety components, while reducing the expense in comparison to known actuation controls.
This and other objects have been achieved according to the present invention by providing actuation control apparatus for controlling a plurality of different passenger safety components in a motor vehicle, comprising: a signal evaluation stage receiving input signals from at least a deceleration sensor, a plurality of output stages receiving signals from said signal evaluation stage, each of said output stages being electrically coupled with a respective actuator of a respective one of said passenger safety components, each of said output stages being adapted to provide an appropriate electrical signal to said respective actuator, at least one of said output stages being adaptable to provide an appropriate electrical signal to any one of at least two different ones of said passenger safety components, said at least one adaptable output stage being presettable to a selected one of said at least two different passenger safety components via an electrical control signal.
This and other objects have been achieved according to the present invention by providing a method for adapting the actuation control apparatus to the passenger safety system of a particular vehicle, wherein during a parametrization procedure, in which the actuation control apparatus is adapted to the specific ones of said passenger safety components present in said particular vehicle, the control signal is set in such a manner that the at least one adaptable output stage is adapted to the passenger safety component designed for adaptation and actually present in said particular vehicle.
This and other objects have been achieved according to the present invention by providing an actuation control apparatus capable of controlling a plurality of different passenger safety components in a motor vehicle and adaptable to specific ones of said passenger safety components which are actually present in the motor vehicle, comprising: at least one output stage which is adaptable to provide an appropriate electrical signal to any one of at least two different ones of said passenger safety components, said at least one output stage being adaptable via an electrical control signal to one of said at least two different passenger safety components which is actually present in the motor vehicle.
The at least one adaptable output stage present in the actuation control apparatus permits covering with only one output stage a series of equipment variants of passenger safety components. Preferably passenger safety components are associated with the adaptable output stages which in all probability are not installed together, such as deployable roll bars and rear seat airbags, and therefore are encountered alternatively.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.